1 /* 2 * kernel userspace event delivery 3 * 4 * Copyright (C) 2004 Red Hat, Inc. All rights reserved. 5 * Copyright (C) 2004 Novell, Inc. All rights reserved. 6 * Copyright (C) 2004 IBM, Inc. All rights reserved. 7 * 8 * Licensed under the GNU GPL v2. 9 * 10 * Authors: 11 * Robert Love <rml@novell.com> 12 * Kay Sievers <kay.sievers@vrfy.org> 13 * Arjan van de Ven <arjanv@redhat.com> 14 * Greg Kroah-Hartman <greg@kroah.com> 15 */ 16 17 #include <linux/spinlock.h> 18 #include <linux/socket.h> 19 #include <linux/skbuff.h> 20 #include <linux/netlink.h> 21 #include <linux/string.h> 22 #include <linux/kobject.h> 23 #include <net/sock.h> 24 25 #define BUFFER_SIZE 2048 /* buffer for the variables */ 26 #define NUM_ENVP 32 /* number of env pointers */ 27 28 /* the strings here must match the enum in include/linux/kobject.h */ 29 const char *kobject_actions[] = { 30 "add", 31 "remove", 32 "change", 33 "move", 34 "online", 35 "offline", 36 }; 37 38 #if defined(CONFIG_HOTPLUG) 39 u64 uevent_seqnum; 40 char uevent_helper[UEVENT_HELPER_PATH_LEN] = "/sbin/hotplug"; 41 static DEFINE_SPINLOCK(sequence_lock); 42 #if defined(CONFIG_NET) 43 static struct sock *uevent_sock; 44 #endif 45 46 /** 47 * kobject_uevent_env - send an uevent with environmental data 48 * 49 * @action: action that is happening (usually KOBJ_MOVE) 50 * @kobj: struct kobject that the action is happening to 51 * @envp_ext: pointer to environmental data 52 * 53 * Returns 0 if kobject_uevent() is completed with success or the 54 * corresponding error when it fails. 55 */ 56 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action, 57 char *envp_ext[]) 58 { 59 char **envp; 60 char *buffer; 61 char *scratch; 62 const char *action_string; 63 const char *devpath = NULL; 64 const char *subsystem; 65 struct kobject *top_kobj; 66 struct kset *kset; 67 struct kset_uevent_ops *uevent_ops; 68 u64 seq; 69 char *seq_buff; 70 int i = 0; 71 int retval = 0; 72 int j; 73 74 pr_debug("%s\n", __FUNCTION__); 75 76 action_string = kobject_actions[action]; 77 if (!action_string) { 78 pr_debug("kobject attempted to send uevent without action_string!\n"); 79 return -EINVAL; 80 } 81 82 /* search the kset we belong to */ 83 top_kobj = kobj; 84 while (!top_kobj->kset && top_kobj->parent) { 85 top_kobj = top_kobj->parent; 86 } 87 if (!top_kobj->kset) { 88 pr_debug("kobject attempted to send uevent without kset!\n"); 89 return -EINVAL; 90 } 91 92 kset = top_kobj->kset; 93 uevent_ops = kset->uevent_ops; 94 95 /* skip the event, if the filter returns zero. */ 96 if (uevent_ops && uevent_ops->filter) 97 if (!uevent_ops->filter(kset, kobj)) { 98 pr_debug("kobject filter function caused the event to drop!\n"); 99 return 0; 100 } 101 102 /* originating subsystem */ 103 if (uevent_ops && uevent_ops->name) 104 subsystem = uevent_ops->name(kset, kobj); 105 else 106 subsystem = kobject_name(&kset->kobj); 107 if (!subsystem) { 108 pr_debug("unset subsytem caused the event to drop!\n"); 109 return 0; 110 } 111 112 /* environment index */ 113 envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL); 114 if (!envp) 115 return -ENOMEM; 116 117 /* environment values */ 118 buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL); 119 if (!buffer) { 120 retval = -ENOMEM; 121 goto exit; 122 } 123 124 /* complete object path */ 125 devpath = kobject_get_path(kobj, GFP_KERNEL); 126 if (!devpath) { 127 retval = -ENOENT; 128 goto exit; 129 } 130 131 /* event environemnt for helper process only */ 132 envp[i++] = "HOME=/"; 133 envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin"; 134 135 /* default keys */ 136 scratch = buffer; 137 envp [i++] = scratch; 138 scratch += sprintf(scratch, "ACTION=%s", action_string) + 1; 139 envp [i++] = scratch; 140 scratch += sprintf (scratch, "DEVPATH=%s", devpath) + 1; 141 envp [i++] = scratch; 142 scratch += sprintf(scratch, "SUBSYSTEM=%s", subsystem) + 1; 143 for (j = 0; envp_ext && envp_ext[j]; j++) 144 envp[i++] = envp_ext[j]; 145 /* just reserve the space, overwrite it after kset call has returned */ 146 envp[i++] = seq_buff = scratch; 147 scratch += strlen("SEQNUM=18446744073709551616") + 1; 148 149 /* let the kset specific function add its stuff */ 150 if (uevent_ops && uevent_ops->uevent) { 151 retval = uevent_ops->uevent(kset, kobj, 152 &envp[i], NUM_ENVP - i, scratch, 153 BUFFER_SIZE - (scratch - buffer)); 154 if (retval) { 155 pr_debug ("%s - uevent() returned %d\n", 156 __FUNCTION__, retval); 157 goto exit; 158 } 159 } 160 161 /* we will send an event, request a new sequence number */ 162 spin_lock(&sequence_lock); 163 seq = ++uevent_seqnum; 164 spin_unlock(&sequence_lock); 165 sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq); 166 167 #if defined(CONFIG_NET) 168 /* send netlink message */ 169 if (uevent_sock) { 170 struct sk_buff *skb; 171 size_t len; 172 173 /* allocate message with the maximum possible size */ 174 len = strlen(action_string) + strlen(devpath) + 2; 175 skb = alloc_skb(len + BUFFER_SIZE, GFP_KERNEL); 176 if (skb) { 177 /* add header */ 178 scratch = skb_put(skb, len); 179 sprintf(scratch, "%s@%s", action_string, devpath); 180 181 /* copy keys to our continuous event payload buffer */ 182 for (i = 2; envp[i]; i++) { 183 len = strlen(envp[i]) + 1; 184 scratch = skb_put(skb, len); 185 strcpy(scratch, envp[i]); 186 } 187 188 NETLINK_CB(skb).dst_group = 1; 189 netlink_broadcast(uevent_sock, skb, 0, 1, GFP_KERNEL); 190 } 191 } 192 #endif 193 194 /* call uevent_helper, usually only enabled during early boot */ 195 if (uevent_helper[0]) { 196 char *argv [3]; 197 198 argv [0] = uevent_helper; 199 argv [1] = (char *)subsystem; 200 argv [2] = NULL; 201 call_usermodehelper (argv[0], argv, envp, UMH_WAIT_EXEC); 202 } 203 204 exit: 205 kfree(devpath); 206 kfree(buffer); 207 kfree(envp); 208 return retval; 209 } 210 211 EXPORT_SYMBOL_GPL(kobject_uevent_env); 212 213 /** 214 * kobject_uevent - notify userspace by ending an uevent 215 * 216 * @action: action that is happening (usually KOBJ_ADD and KOBJ_REMOVE) 217 * @kobj: struct kobject that the action is happening to 218 * 219 * Returns 0 if kobject_uevent() is completed with success or the 220 * corresponding error when it fails. 221 */ 222 int kobject_uevent(struct kobject *kobj, enum kobject_action action) 223 { 224 return kobject_uevent_env(kobj, action, NULL); 225 } 226 227 EXPORT_SYMBOL_GPL(kobject_uevent); 228 229 /** 230 * add_uevent_var - helper for creating event variables 231 * @envp: Pointer to table of environment variables, as passed into 232 * uevent() method. 233 * @num_envp: Number of environment variable slots available, as 234 * passed into uevent() method. 235 * @cur_index: Pointer to current index into @envp. It should be 236 * initialized to 0 before the first call to add_uevent_var(), 237 * and will be incremented on success. 238 * @buffer: Pointer to buffer for environment variables, as passed 239 * into uevent() method. 240 * @buffer_size: Length of @buffer, as passed into uevent() method. 241 * @cur_len: Pointer to current length of space used in @buffer. 242 * Should be initialized to 0 before the first call to 243 * add_uevent_var(), and will be incremented on success. 244 * @format: Format for creating environment variable (of the form 245 * "XXX=%x") for snprintf(). 246 * 247 * Returns 0 if environment variable was added successfully or -ENOMEM 248 * if no space was available. 249 */ 250 int add_uevent_var(char **envp, int num_envp, int *cur_index, 251 char *buffer, int buffer_size, int *cur_len, 252 const char *format, ...) 253 { 254 va_list args; 255 256 /* 257 * We check against num_envp - 1 to make sure there is at 258 * least one slot left after we return, since kobject_uevent() 259 * needs to set the last slot to NULL. 260 */ 261 if (*cur_index >= num_envp - 1) 262 return -ENOMEM; 263 264 envp[*cur_index] = buffer + *cur_len; 265 266 va_start(args, format); 267 *cur_len += vsnprintf(envp[*cur_index], 268 max(buffer_size - *cur_len, 0), 269 format, args) + 1; 270 va_end(args); 271 272 if (*cur_len > buffer_size) 273 return -ENOMEM; 274 275 (*cur_index)++; 276 return 0; 277 } 278 EXPORT_SYMBOL_GPL(add_uevent_var); 279 280 #if defined(CONFIG_NET) 281 static int __init kobject_uevent_init(void) 282 { 283 uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 1, NULL, 284 NULL, THIS_MODULE); 285 286 if (!uevent_sock) { 287 printk(KERN_ERR 288 "kobject_uevent: unable to create netlink socket!\n"); 289 return -ENODEV; 290 } 291 292 return 0; 293 } 294 295 postcore_initcall(kobject_uevent_init); 296 #endif 297 298 #endif /* CONFIG_HOTPLUG */ 299